Retrieval systems and methods for use thereof

ABSTRACT

The devices and methods described herein relate to improved structures for removing obstructions from body lumens. Such devices have applicability in through-out the body, including clearing of blockages within the vasculature, by addressing the frictional resistance on the obstruction prior to attempting to translate and/or mobilize the obstruction within the body lumen

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Application No. 12,344,378filed Dec. 26, 2008 which claims benefit of priority to U.S. ProvisionalApplication No. 61/016,651 filed on Dec. 26, 2007, the entirety of whichare incorporated by reference herein.

FIELD OF THE INVENTION

The devices described herein are intended to retrieve obstructions fromthe body. In a first variation, the devices are constructed in wire formwhere the wires diverge from a main bundle to form a variety of shapesthat form a composite device. The benefit of such a diverging wireconstruction is that the composite complex device can be of a“joint-less” construction. Such devices have applicability through outthe body, including clearing of blockages within body lumens, such asthe vasculature, by providing a capturing portion that can envelop theobstruction to address the frictional resistance between the obstructionand body lumen prior to attempting to translate and/or mobilize theobstruction within the body lumen. In addition, the devices describedbelow include features that prevent unwanted and premature mobilizationof the obstruction when removing the obstruction through tortuousanatomy.

BACKGROUND OF THE INVENTION

Many medical device applications require advancement of device in areduced profile to a remote site within the body, where on reaching atarget site the device assumes or is deployed into a relatively largerprofile. Applications in the cerebral vasculature are one such exampleof medical procedures where a catheter advances from a remote part ofthe body (typically a leg) through the vasculature and into the cerebralregion of the vasculature to deploy a device. Accordingly, the deployeddevices must be capable of achieving a larger profile while being ableto fit within a small catheter or microcatheter. In addition, the degreeto which a physician is limited in accessing remote regions of thecerebral vasculature is directly related to the limited ability of thedevice to constrain into a reduced profile for delivery.

Treatment of ischemic stroke is one such area where a need remains todeliver a device in a reduced profile and deploy the device toultimately remove a blockage in an artery leading to the brain. Leftuntreated, the blockage causes a lack of supply of oxygen and nutrientsto the brain tissue. The brain relies on its arteries to supplyoxygenated blood from the heart and lungs. The blood returning from thebrain carries carbon dioxide and cellular waste. Blockages thatinterfere with this supply eventually cause the brain tissue to stopfunctioning. If the disruption in supply occurs for a sufficient amountof time, the continued lack of nutrients and oxygen causes irreversiblecell death (infarction). Accordingly, immediate medical treatment of anischemic stroke is critical for the recovery of a patient.

Naturally, areas outside of ischemic stroke applications can alsobenefit from improved devices. Such improved devices can assume aprofile for ultimate delivery to remote regions of the body and canremove obstructions. There also remains a need for devices and systemsthat can safely remove the obstruction from the body once they aresecured within the device at the target site. Furthermore, there remainsa need for such devices that are able to safely removed once deployeddistally to the obstructions in the even that the obstructions is unableto be retrieved.

Accordingly, a need remains for devices that can assume deployedconfigurations and are fabricated to eliminate or reduce the number ofjoints and/or connection points in the device.

SUMMARY OF THE INVENTION

The examples discussed herein show the inventive device in a form thatis suitable to retrieve obstructions or clots within the vasculature.The term obstructions may include blood clot, plaque, cholesterol,thrombus, naturally occurring foreign bodies (i.e., a part of the bodythat is lodged within the lumen), a non-naturally occurring foreign body(i.e., a portion of a medical device or other non-naturally occurringsubstance lodged within the lumen.) However, the devices are not limitedto such applications and can apply to any number of medical applicationswhere elimination or reduction of the number of connection points isdesired.

One variation of the device includes a medical device for removing anobstruction from a blood vessel, the medical device comprises a mainbundle comprising a group of wires having a first end and a second end,a capturing portion formed by the group of wires and having atranslating surface adjacent to a capturing surface, the translatingsurface having an open proximal end and the capturing surface having apermeable distal end, where the capturing portion is formed from thegroup of wires such that the group of wires diverges from the second endof the main bundle to form the permeable distal end, the group of wiresextend back in a proximal direction to form the capturing surface, thetranslating surface, and open proximal end about the main bundle; andwhere the translating surface and capturing surface are configured sothat a translating surface axial strength is greater than a capturingsurface axial strength, wherein application of a tensile force on themain bundle causes axial compression of the capturing surface withoutcausing axial compression and deformation of the translating surfacesufficient to deform the translating surface as the capturing portionengages the obstruction.

The medical device can include a capturing surface that is configured togenerate a spring force against the translating surface when a proximalforce applied by the main bundle of wires compresses the capturingsurface against the translating surface when encountering resistancefrom the obstruction, where the capturing surface is configured to havea sufficient axial stiffness to direct the spring force and proximalforce to the open proximal end as the open proximal end engages theobstruction where the capturing surface is also sufficiently flexible toconform to a shape of the vessel.

In another variation, the capturing section is configured so that whenthe open proximal end of the translating section engages resistanceequal to or greater than a threshold force, proximal movement of theleading wire inverts the capturing section within the translatingsection and reduces a size of the capturing section to enable thecapturing section to re-enter a catheter.

In those variation of the device that are navigated in tortuous anatomy(such as the cerebral vasculature), the device can include a main bundlejoined to a proximal bundle, where the proximal bundle comprises astiffness greater than the main bundle and where the main bundle extendsfor at least a predetermined range from the permeable distal end toallow navigation of a distal portion of the medical device within thecerebral vasculature.

Another variation of the device includes a retrieval device for removingan obstruction from a body lumen, the system comprising at least oneleading wire; a retrieval body comprising a translating section adjacentto a capturing section, the translating section having an open proximalend and the capturing section having a permeable distal end, where theleading wire is extends to a portion of the capturing section to permitarticulation of the open proximal end relative to the leading wire; andwhere the translating section and capturing section are configured sothat a translating section axial strength is greater than a capturingsection axial strength, wherein application of a tensile force on theleading wire causes axial compression of the capturing surface withoutcausing axial deformation of the translating surface when the retrievalbody engages the obstruction.

Variations of the retrieval system can also include a sheath having ahub located at a proximal end, a proximal capture portion affixed to adistal end of the sheath, at least one leading wire extending throughthe sheath, where a distal section of the leading wire comprises adistal stiffness and where a proximal section of the leading wirecomprises a proximal stiffness, where the proximal stiffness is greaterthan the distal stiffness, a distal capturing portion at the distal endof the leading wire, the distal capturing portion being axially moveablerelative to the proximal capture portion, and an insertion tool slidablylocated over the sheath, the insertion tool comprising a gripping regionaffixed to a rigid section, where compression of the gripping portioncreates a frictional fit between the insertion tool such that when theinsertion tool is coupled to the catheter, compression of the grippingportion and axial movement of the insertion tool advances the sheathwithin the catheter.

In one variation of the devices described herein, the device comprises amain bundle or group of wires that diverge to form a device havingvarious shapes but few or no connections points or joints (wherefabrication of such a construction is referred to as “jointless”).Clearly, the inventive devices described herein are not limited to sucha jointless construction. Additional variation includes one or moreleading wires that are attached to a capturing portion as describedbelow.

In another variation, the device includes a main bundle comprising oneor a group of wires. The device also includes a capturing portion formedby the wires or wire of the main bundle. The capturing portion includesa cavity or space that is able to surround the obstruction. Accordingly,the capturing portion includes an open proximal end, a permeable distalend, and a capturing surface extending therebetween. The permeabledistal end should be sufficiently permeable to allow blood to flow buthave sufficient surface area to prevent escape of the obstruction or toprevent particles such as pieces of clot or emboli that would otherwisecause a complication if such pieces migrate through the body. In somevariations of the device, the capturing portion is formed from the groupof wires such that the group of wires diverges from the second end ofthe main bundle to form the permeable distal end, the group of wiresextend back in a proximal direction to form the capturing surface andopen proximal end about the main bundle. Although some closing of theopen proximal end can occur, it will not be sufficient to interfere withthe obstruction as the capturing portion moves over the obstruction. Insome variations, the permeable end may be the distal end or be towardsthe distal end (meaning anywhere past a proximal end). The terms distaland proximal are relative to the physician (e.g., the distal end is thefarthest end from the catheter/physician).

The devices of the present invention typically include a main bundlefrom which the wires extend. In most case, the main bundle extends for alength sufficient to withdraw the device from a body of a patient.Accordingly, in such cases, the main bundle shall extend through thelength of a catheter. In alternate constructions, the main bundle may beaffixed to a single wire or member. In such cases, a main bundle doesnot extend from the capturing portion to the exterior of the patient.Instead, a single wire extends to the operator interface of the devicewhere the wire is affixed to a main bundle.

Devices of the present invention can incorporate any number of wires ofdifferent characteristics including, but not limited to, materials,shapes, sizes and/or diameters. Clearly, the number of permutations ofdevice configurations is significant. Providing devices with such acomposite construction allows for the manipulation of the device'sproperties to suite the intended application.

In an additional variation, the surface of the capturing portion caninclude a wire frame structure, a mesh, a single wound wire, a film, amembrane, a polymer covering, and a plurality of crossing wires or aheterogeneous mixing of these. In additional variations, a section ofthe capturing portion can include wires, while another section of thecapturing portion can include a film. Clearly, any number ofpermutations is within the scope of this disclosure. In any case, thecapturing surface should prevent the obstruction from escaping as thedevice is removed from the body. Clearly, the capturing surface cancomprise any number of shapes or configurations.

As noted herein, the joint-less construction improves the flexibilityand strength of the device by eliminating joints, connection points, orother attachment points. In addition, the joint-less constructionimproves the ability of the device to be delivered through a smallmicrocatheter. As a result, the device and microcatheter are able toaccess remote regions of the vasculature.

The devices may be fabricated to be self-expanding upon deployment froma catheter. Alternatively, the devices can be constructed fromshape-memory alloys such that they automatically deploy upon reaching apre-determined transition temperature.

The devices of the present invention may also include features toprevent migration of the obstruction as the capturing portionencapsulates the obstruction. For example, a proximal foot (such asregion of increased surface area) can be located on or in the catheter.In another variation, an additional capture portion is located on thecatheter where the proximal end of this capture is a mesh, a singlewound wire, a film, a membrane, a polymer covering, or a plurality ofcrossing wires affixed to or in the catheter. Accordingly, the capturingportions both envelope or surround the obstruction as they are movedtogether. As noted below, additional variations may allow fortemporarily locking of the two capturing portions together for increaseeffectiveness in removing the obstruction from the body.

The capturing portions disclosed herein can include mechanical featuresthat assist in removal of the obstruction. These features can be hooks,fibers, barb, or any such structure. Any portion of the capturingportion or even the device can have such hooks, fibers, or barbs thatgrip into the obstruction as the device surrounds the obstruction. Itwill be important that such features prevent the obstruction fromsliding proximally but do not hinder the ability of the practitioner toremove the device from the body.

The operation of the devices and method described herein secure theobstruction, overcome the friction forces acting on the obstruction, andthen remove the obstruction from the anatomy without losing orfractionating the obstruction. In a first variation, the inventivemethod includes advancing a catheter distal to the obstruction,deploying a first capturing portion distal of the obstruction, where thefirst capturing portion comprises a translating surface and a capturingsurface, the translating surface having an open proximal end and thecapturing surface having a permeable distal end, and at least oneleading wire affixed to the capturing surface and extending through thecapturing portion and through the catheter, where the translatingsurface and capturing surface are configured so that a translatingsurface axial strength is greater than that of a capturing surface axialstrength, proximally moving the leading wire to compress the capturingsurface without compressing the translating surface such that thetranslating surface gradually advances over the obstruction, andremoving the obstruction and first capturing portion from the bloodvessel

Additional variations of the method include (1) passing a catheterdistally to the obstruction by passing either through the obstructionand/or between the obstruction and the vascular wall; (2) deploying afirst capturing portion distally to the obstruction and the catheter iswithdrawn proximal to the obstruction; (3) the capturing portion is thentranslated over the obstruction by withdrawing the main bundle. Sincethe main bundle is affixed to a distal end of the capturing portion,misalignment between the bundle and the capturing portion does not causedistortion of the open proximal end. Since the open proximal end remainsexpanded against the lumen wall, the capturing portion can then beadvanced over the obstruction.

The method and systems may also include the use of an additionalcapturing portion having an open distal end. This configuration allowsthe first capturing portion and second capturing portion to envelop orensnare the obstruction from both the proximal and distal sides.Additional variations even allow for temporarily locking the twocapturing portions together. Such a feature increases the ability toremove the obstruction from the body

It should be noted that reference to surrounding, capturing or securingthe obstruction includes partially and/or fully surrounding, engulfing,encapsulating, and/or securing the obstruction. In any case, a portionof the device engages the obstruction prior to translation of theobstruction within the lumen.

It should be noted that in some variations of the invention, all or someof the device can be designed to increase their ability to adhere to theobstruction. For example, the wires may be coupled to an energy source(e.g., RF, ultrasonic, or thermal energy) to “weld” to the obstruction.Application of energy to the device can allow the surrounding portion todeform into the obstruction and “embed” within the obstruction.Alternatively, the device can impart a positive charge to theobstruction to partially liquefy the obstruction sufficiently to allowfor easier removal. In another variation, a negative charge could beapplied to further build thrombus and nest the device for better pullingforce. The wires can be made stickier by use of a hydrophilicsubstance(s), or by chemicals that would generate a chemical bond to thesurface of the obstruction. Alternatively, the filaments may reduce thetemperature of the obstruction to congeal or adhere to the obstruction.

Additional variations of the invention include a reentry device forwithdrawing an object into a distal end of a sheath, the reentry devicecomprising a elongate member having a distal portion and a lumenextending therethrough, a plurality of first tines arrangedcircumferentially at the distal portion, the plurality of first tineseach having a distal end forming a first discontinuous funnel where thedistal end of each first tine is spaced from the distal end of anadjacent first tine, wherein the first discontinuous funnel iscollapsible upon withdrawal into the distal end of the sheath, a secondfunnel spaced proximal to the first funnel, where the second funnel iscollapsible upon withdrawal into the distal end of the sheath, andwherein a distal perimeter of the first discontinuous funnel shape isdistal to a distal perimeter of the second funnel.

In an additional variation, the second funnel comprises a plurality ofsecond tines arranged circumferentially at the distal portion, theplurality of second tines each having a distal end forming a seconddiscontinuous funnel shape where the distal end of each second tine isspaced from the distal end of an adjacent second tine.

Another example of a reentry device includes an elongate member having adistal portion and a lumen extending therethrough, the elongate membersized to slidably fit within the sheath, a first slotted funnelcomprising a plurality of first tines each having free endsdiscontinuous with free ends of adjacent first tines, where the firstslotted funnel is collapsible upon withdrawal into the distal end of thesheath; and a second funnel located proximal to the free ends of thefirst tines.

The reentry device can also comprises a retrieval system for withdrawingan object into a distal end of a sheath. The term sheath, when used witha reentry device, is intended to include any tube, introducer, sheath,or access device. Typically, when the retrieval device is used withneurovascular retrieval devices, the sheath will be a femoral accesssheath or device. Regardless, the reentry device includes a firstelongate member having a distal portion and a lumen extendingtherethrough, a second elongate shaft extending through the firstelongate member, a flexible layer having a first end inverted on adistal end of the second elongate shaft and a second end affixed to anexterior of the first elongated shaft, where decreasing a distancebetween the distal end of the second elongate shaft and the exterior ofthe first elongated member causes the flexible material to form a funnelwhen the flexible layer further inverts about the second elongate shaft.

Additional devices and methods for treating ischemic stroke arediscussed in commonly assigned U.S. patent application Ser. No.11/671,450 filed Feb. 5, 2007; Ser. No. 11/684,521 filed Mar. 9, 2007;Ser. No. 11/684,535 filed Mar. 9, 2007; Ser. No. 11/684,541 filed Mar.9, 2007; Ser. No. 11/684,546 filed Mar. 9, 2007; Ser. No. 11/684,982filed Mar. 12, 2007, Ser. No. 11/736,526 filed Apr. 17, 2007, Ser. No.11/736,537 filed Apr. 17, 2007, and Ser. No. 11/825,975 filed Sep. 10,2007; the entirety of each of which is incorporated by reference. Theprinciples of the invention as discussed herein may be applied to theabove referenced cases to produce devices useful in treating ischemicstroke. In other words, the wire-shaped construction of devicesaccording to present invention may assume the shapes disclosed in theabove-referenced cases when such a combination is not inconsistent withthe features described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Each of the following figures diagrammatically illustrates aspects ofthe invention. Variation of the invention from the aspects shown in thefigures is contemplated.

FIG. 1A illustrates an example of a device according to the presentinvention when used in a system for removing obstructions from bodylumens.

FIG. 1B illustrates a first example of an obstruction removal medicaldevice.

FIG. 1C illustrates the obstruction removal device articulating relativeto leading wires (or a main bundle) without deforming an open end of thecapturing portion.

FIGS. 2A to 2E show a capturing portion for use with systems describedherein where the capturing portion has sections of varying axialstrengths. Such features can optionally be designed to provide a springforce when a section of the capturing portion is compressed and/orstaged inversion of the capturing portion so that it can be removedthrough an immovable obstruction.

FIG. 3A illustrates a first variation of the device having a joint-lessconstruction of a capturing portion that articulates about a main bundleof wires.

FIGS. 3B to 3H illustrate various constructions of capturing portionsfor use in the present invention.

FIG. 4A illustrates a variation of a capturing portion having a mainbundle that extends beyond a certain distance to provide a device havingan extremely flexible distal region and a relatively stiff proximalregion with a strong joint region that will be sufficiently spaced fromtortuous anatomy during use of the device.

FIG. 4B illustrates a main bundle having a curved or shaped portion.

FIGS. 4C to 4E illustrate wires of different constructions within a mainbundle.

FIG. 5A illustrates am example of a proximal foot located on a catheterof the present system.

FIG. 5B illustrates a distal and a proximal capturing portion located ona system under the present invention.

FIGS. 5C to 5E illustrate an overview of a variation of a deliverysystem employing a proximal and distal capturing portion.

FIG. 5F illustrates compression or collapsing of a proximal capturingportion about an obstruction prior to translation of the obstruction inthe vessel.

FIGS. 6A to 6B illustrate an example of traversing an obstruction with asheath to deploy a distal capturing portion.

FIGS. 7A to 7C illustrates a condition where a section of the capturingportion deflects to provide a spring force that gradually drives atraversing section along the obstruction.

FIGS. 7D to 7G illustrate staged inversion of the distal capturingportion to allow removal of the device from an immovable clot.

FIG. 8A illustrates closure of the proximal opening of a capturingportion without the benefit of articulation of the capturing portionabout a leading wire.

FIG. 8B illustrates, conceptually, one benefit of articulation of acapturing portion about a leading wire or main bundle of wires.

FIGS. 8C to 8D illustrate a proximal capturing portion and a distalcapturing portion approaching an obstruction.

FIG. 8E illustrates the system as two capturing portions are drawntogether.

FIG. 8F illustrates a device after securing an obstruction betweenproximal and distal capturing sections.

FIG. 9 illustrates a main bundle as including an increased surface areaor medial foot that is used to dislodge or loosen the obstruction from awall of the body passage.

FIG. 10 illustrates a variation of a proximal and distal end of aretrieval device.

FIGS. 11A to 11C illustrate a variation of a funnel catheter useful forretrieving objects from vessels or body lumens.

FIG. 12A shows an example of a retrieval device getting caught on aguide sheath.

FIGS. 12B to 12C provide illustrative examples of funnel catheter usedfor removal of an obstruction.

FIG. 12D illustrates a dual funnel catheter having a discontinuous firstfunnel and a second funnel.

FIG. 13A to 13G illustrates another variation of a funnel catheter usinga mesh or layer of material to form a funnel.

FIGS. 14A to 14D illustrate additional concepts to prevent or minimizeflaring of the distal capture portion so that it may be withdrawn into aguide sheath.

DETAILED DESCRIPTION

It is understood that the examples below discuss uses in the cerebralvasculature (namely the arteries). However, unless specifically noted,variations of the device and method are not limited to use in thecerebral vasculature. Instead, the invention may have applicability invarious parts of the body. Moreover, the invention may be used invarious procedures where the benefits of the method and/or device aredesired.

FIG. 1A illustrates a system 10 for removing obstructions from bodylumens as described herein. In the illustrated example, this variationof the system 10 is suited for removal of an obstruction in the cerebralvasculature. Typically, the system 10 includes a catheter 12microcatheter, sheath, guide-catheter, or simple tube/sheathconfiguration for delivery of the obstruction removal device to thetarget anatomy. The catheter should be sufficient to deliver the deviceas discussed below. The catheter 12 may optionally include an inflatableballoon 18 for temporarily blocking blood flow or for expanding thevessel to release the obstruction.

It is noted that any number of catheters or microcatheters maybe used tolocate the catheter/microcatheter 12 carrying the obstruction removaldevice 200 at the desired target site. Such techniques are wellunderstood standard interventional catheterization techniques.Furthermore, the catheter 12 may be coupled to auxiliary or supportcomponents 14, 16 (e.g., energy controllers, power supplies, actuatorsfor movement of the device(s), vacuum sources, inflation sources,sources for therapeutic substances, pressure monitoring, flowmonitoring, various bio-chemical sensors, bio-chemical substance, etc.)Again, such components are within the scope of the system 10 describedherein.

In addition, devices of the present invention may be packaged in kitsincluding the components discussed above along with guiding catheters,various devices that assist in the stabilization or removal of theobstruction (e.g., proximal-assist devices that holds the proximal endof the obstruction in place preventing it from straying during removalor assisting in the removal of the obstruction), balloon-tipped guidecatheters, dilators, etc.

FIG. 1B illustrates a first example of an obstruction removal medicaldevice according to the features described herein. As shown, the device200 generally includes capturing portion 226 comprising a translatingsection/surface 222 and a capturing section/surface 224. In theillustrated variation, the translating section 222 shown comprises awire framework. However, any number of configurations is within thescope of this disclosure. In many variations of the device, thetranslating section 222 provides a low friction surface so that ittranslates over the obstruction without significantly moving theobstruction. This permits the capturing portion 226 to envelop orsurround the obstruction prior to attempting to move the obstructionwithin the body lumen. As noted herein, the translating section 222attempts to reduce the outward radial force applied by the obstructionagainst the wall of the lumen during movement of the obstruction withinthe lumen.

FIG. 1B illustrates a distal section of the capturing portion 226 thatserves as a capturing section/surface 232. The capturing section 232 hasan increased frictional surface (in this variation illustrated by thecrossing 204 wires) so that it can capture and ultimately remove theobstruction. The frictional surface of the capturing section 232 canalso be described as an increased coverage density. In essence, as thefrictional surface of capturing section 232 coverage density increases,there is a greater “device” surface area to interact with theobstruction. In some variations the capturing section 232 increases infrictional surface between the translating section 234 and the end ofthe device 200.

As shown, the device 200 includes a main bundle 202 comprising a groupof individual leading wires 204. In this variation, the bundle ofleading wires 204 is surrounded by a coil or coiled wire 205. The coiledwire 205 can comprise a single leading wire that joins the device 202.Alternatively, the coiled wire 205 can extend terminate or wrap backprior to forming the capture portion 226. Moreover, the coiled wire 205can extend throughout a length the main bundle 202, or along one or moresegments of the main bundle 202.

While the example shows the group consisting of four individual leadingwires 204, the bundle 202 can have any number of leading wires. Invarious examples 2, 4, or 8 wires were used to construct the device. Incertain variations, the number of wires in the main bundle loop aroundfrom the capturing portion. For example, if 2 leading wires are used toconstruct the device, then when constructing the main bundle 202 2 wiresare set to extend distally towards the capturing portion, where the 2wires are then shaped to form the capturing portion. Eventually, thewires then loop back to extend proximally away from the capturingportion. Therefore, the 2 wires are doubled in the main bundle to create4 separate wires in the main bundle.

The individual wires 204 themselves may be comprised of a number ofdifferent “micro” filaments, wires, or a single type of wire. Variationsof the wires 204 are discussed in detail below; however, the wires 204can be strands, filaments, or any similar structure that is able to bejoined to form the device. The bundle 202 may be braided, wrapped,twisted, or joined in any manner such that they do not separate orbecome unbundled except where desired. For example, wires in any sectionof the device 200 can be bonded together (e.g., with epoxy, a polymericcoating, weld, solder, and/or adhesive, etc.) to prevent the wires fromseparating during deformation of the device as it deploys or removes theobstruction. In addition, the main bundle 202 can incorporate any numberof features to assist in orienting the device 200 within the bodypassage. For example, the main bundle 202 can include a pre-set bendthat would bias the capturing portion 226 in a desired orientation upondeployment as discussed below.

As also discussed below, variations of the present device 200 includecapturing portions 226 where the translating section 234 provides agreater axial strength than an axial strength of the capturing section232. The axial strength (e.g., column strength) determines whether therespective section of the capturing portion 226 compresses when thedevice 200 encounters resistance from an object and as a proximal orpulling force is applied through the main bundle or leading wire 202. Inuse, the translating section 234 resists axial compression anddeformation so that it can locate about the obstruction. While thenature of moving the translating section will place the structure in astate of compression, there will be no visible deformation or deflectionthat prevents the translating section from advancing across anobstruction.

There are a number of approaches to adjust the axial strength of acapturing section 232 as well as the entire structure. In a firstexample, the manner in which the leading wire is wound to form therespective surface 232, 234 impact the respective axial strength. Asshown, the traversing section 234 comprises a series of wrapped wiresextending in an axial direction. This axial alignment causes the wiresto oppose axial forces and thus increases the axial strength of thetraversing section 234 relative to the capturing section 232. In thelatter section, the wires 232 extend in a helical direction about thesection 232. Thus there is less resistance to an axial load whencompared to the traversing section 234.

Alternatively, or in combination, additional techniques can produce adevice 200 with a capturing portion 226 that has sections of varyingaxial strength. In one example, the wire diameter can be adjusted toproduce the desired column strength. Generally, for a givenconstruction, a larger diameter wire increases the column strength ofthe section. In addition, larger diameter leading wires can terminate atthe translating section 234 to permit smaller diameter wires to form thecapturing section 232. In another example, the leading wire 204composition can be selected to produce the desired axial strength. Forexample, drawn filled tube (DFT) wire has 30% platinum 70% nitenol.Decreasing the amount of platinum and increasing the nitenol increasesthe wire strength and results in higher column strength. In yet anotherexample, the respective section, or the entire capturing portion 226,can be processed to produce the desired axial strength. For example,changing the annealing profile (e.g., temp, time) affects the wirestrength, and therefore the axial strength.

Variations of devices 200 described herein can have capturing portionswith alternate configurations than those shown in above. The capturingportion 226 can include constructional designs such as a basket, afilter, a bag, a coil, a helical wire structure, a mesh, a single woundwire, a film, a membrane, a polymer covering, or a plurality of crossingwires. In variations of the device, the capturing portion 226 issufficiently permeable to allow blood or other fluid flow therethrough.As noted above, capturing portion 226 may be any structure that covers,encapsulates, engulfs, and/or ensnares the obstruction either fully orpartially. Accordingly, although the capturing portion 226 isillustrated as a filter/bag, the wires may diverge to form a coil,helical shape, other mesh structure, or any other structure that definesa space that can be translated over the obstruction to ultimately removethe obstruction 2.

The capturing portion 226 can include an open proximal end 228, apermeable distal end 230 and a capturing surface 232 locatedtherebetween. The capturing surface 232 of the capturing portion 226defines a volume, cavity, or space that is able to cover, encapsulate,envelop, engulf, ensnare and/or surround the obstruction. Generally, theterm traversing wire or filament refers to the section of leading wire204 that forms the traversing surface 238. Generally, the traversingwires form the capturing surface 238 and then form the open proximal end228. As discussed herein and illustrated below, the open proximal end228 expands within the lumen, typically to the lumen walls, so that theobstruction enters the open proximal end 228 as the bundle 202 (orleading wire) translates the device 200 proximally.

The permeable distal end 230 is typically sufficiently porous so thatfluid or blood may flow through. However, the end 230 is sufficientlyclosed (or has an increased surface area) so that the obstruction shouldnot escape through the distal end 230 of the device 200. Thisconstruction typically causes the the obstruction to become ensnaredwithin the capturing portion 226 and prevented from passing through bythe permeable distal end 230.

As shown in FIG. 1C, an important feature of the present devices 200 isthat the main bundle 202 and capturing portion 226 can articulaterelative to one another without interfering with the size or profile ofthe open proximal end 228. This feature is described more fully below.As shown, the main bundle 202 extends through the open proximal end 228and through at least a the traversing section 234 capturing portion 226.

FIG. 1C illustrates a condition where the main bundle 202 and capturingportion 226 articulate relative to one-another. Because the main bundle202 joins the capturing section 232 at a distance from the open proximalend 228 movement of the main bundle 202 relative to an axis 236 of thecapturing portion 226 does not reduce a profile of the open proximal end228. If the main bundle 202 were affixed or connected to the openproximal end 228, then any movement of the bundle 202 away from thecapturing portion's axis 236 would exert a force on the open end. Thisforce, in turn, would cause the open end to narrow or deform. By doingso, the open end would not be able to uniformly expand against the lumenwall to capture the obstruction.

Turning now to the construction of the device 200, as shown above, themain bundle or a leading wire 202 extends beyond the open proximal end228 and forms the capturing portion. In one variation, the constructionof the device relies on converging/diverging wires to form continuousshapes so that the device is completely joint or connection free.However, as noted herein, the leading wire or main bundle 202 can beaffixed to a structure that forms the capturing portion via anattachment point, joint, or junction. In addition, the structuresforming the capturing portion can be fabricated from such processes aslaser cutting of tubes, etching, metal injection molding, or any othersuch process.

The devices of the present invention can also include additionalfeatures to aid in removal of obstructions. For example, as shown inFIGS. 1B to 1C, the open proximal end 228 can include one or more petalsor flanges 238 extending radially outward. The flanges 238 allow device200 to have a flared structure at the open proximal end 228. In oneexample, the capturing portion 226 can be slightly oversized relative tothe body passage containing the obstruction or slightly larger than thecapturing portion. The flanges 238 provide an additional force againstthe wall of the passage to ensure that the device 200 is able tosurround or encapsulate the obstruction. In yet another feature, invariations of a system having a proximal and distal capturing portion,the flanges can serve to lock the proximal and distal capturing portionstogether once they encapsulate or surround an obstruction. This featureminimizes the chance that the obstruction escapes from the capturingportions as the device and obstruction are removed from the body lumen.

In additional variations, the main bundle can diverge to form thecapturing portion in multiple locations so long as the capturingportion's ability to articulate is not sacrificed. For example, the mainbundle can diverge in several locations along the capturing surface (notshown).

FIGS. 1B to 1C also shows an integrally formed reinforcement ring 240located along the length of the capturing surface 232 (i.e., on thetraversing wires). The reinforcement ring 240 can be a separate ordiscrete ring located on or in the capturing surface 232. Alternatively,or in combination, the reinforcement ring 240 can be a ring shape thatis integrally formed through arrangement of the wires 204 (as show inFIGS. 1B to 1C). The reinforcement ring 240 assists in expanding thedevice when deployed in the body lumen and/or prevents the device (e.g.,the open proximal end) from collapsing as the device moves within thelumen to secure the obstruction. The reinforcement ring 240 can comprisea single wire, or a twisted pair of wires. Alternatively, the rings donot need to extend entirely circumferentially around the capturingsurface. Instead, a reinforcement portion may extend between adjacenttraversing wires but does not necessarily extend around thecircumference of the capturing section. As noted herein, reinforcementportions may extend between adjacent traversing wires in multiplelocations.

FIGS. 2A to 2E show several benefits of varying axial strengths of thedifferent sections of a capture portion 226. As shown in FIG. 2A, whenthe physician retrieves the capturing portion 226 by pulling on theleading wire or main bundle 202 (as shown by arrow 120), the entirecapturing portion 226 translates as shown by arrow 122. However, whenthe device 200 encounters resistance (as schematically shown by forcearrows 124) the lesser axial strength of the capturing section 232causes axial deformation or compression of the capturing section 232 (asshown by FIG. 2B). In certain variations, the capturing section 232 canbe constructed to function as spring such that deformation of thecapturing section 232 stores energy. Accordingly, the physician can pullthe main bundle 202 to build energy in the capturing section 232, thenrelax the force on the main bundle 202. The stored energy in thecapturing section 232 gradually drives the open proximal end of thetranslating section 234 over or along the obstruction. The physician canapply this “pull and relax” technique repeatedly until the obstructionis sufficiently captured by the capturing portion 226.

FIG. 2C shows an additional safety benefit given the varying axialstrengths of the different sections of a capture portion 226. In theevent the capturing portion 226 encounters an excessive degree orthreshold of force (as denoted by arrows 124), the reduced axialstrength of the capturing section 232 can invert within the translatingsection 234. As shown, the permeable distal end 230 of the capturingsection 232 inverts and is pulled by the main bundle 202 within thetranslating section 234 and reduces in size. As shown in FIG. 2D,continued pulling on the main bundle 202 causes eventual inversion ofthe translating section 234 so that the capturing section 232 extendsthrough the translating section 234 and the permeable distal end 230 isnow proximal to the translating section 234. Continuing to apply movethe main bundle 202 in a proximal direction 120 inverts the capturingportion 226 as shown in FIG. 2E. As shown, the translating section 234is now distal to the capturing section 232. This causes a reduction inthe size of the capturing portion through inversion of the capturingportion 226. This feature permits withdrawal of the capturing portion226 within a delivery sheath 106 or through an immobile obstruction (asdiscussed below). As shown below, the ability to sequentially invert thecapturing portion 226 and reduce its diameter enables retrieval of thedevice if deployed distal to atherosclerotic plaque or an immobileobject where continued pulling against the object could cause damage ortearing of the body passage or vessel wall. It was found that retrievaldevices that are not constructed with regions of varying axial strength,spring function, or staged inversion can often flatten or expand indiameter when attempting to retrieve the device though an immobile orstubborn obstruction.

FIG. 3A illustrates an additional variation of a capturing portions 226according to the present disclosure. In FIG. 3A, the main bundle 202 andthe group of wires 204 branch or diverge at the permeable distal end 230to form the capturing portion 226. In additional variations, the mainbundle 202 can branch or diverge within a mid-portion of the capturingsurface 232 rather than at the permeable distal end 230. In such a case,the wires 204 form the capturing surface 232 first and ultimately branchto form the remainder of the capturing portion. In any case, byextending through the open proximal end 228, the main bundle 202 is ableto articulate relative to the capturing portion 226 withoutsignificantly reducing a profile of the open distal end 228. Asdiscussed above, the capturing surface 232 of these variations isfabricated (either through processing or wire construction) to have anaxial strength that is lower than that of the traversing section 234.

FIG. 3B illustrates a variation having an integrated reinforcement ring240. Typically, the reinforcement ring 240 provides radial strength tothe capturing portion 226 to prevent collapse or deformation that wouldotherwise interfere with enveloping the obstruction. A reinforcementring 240 may allow for use of wires that would otherwise provideunacceptable radial strength. For example, the reinforcement ring 240may permit use of smaller diameter wires thereby allowing the device 200to compress to a smaller diameter during delivery via a catheter.

In addition to the reinforcement ring 240, FIG. 3B includes an openproximal end 228 having a number of petals/flanges 238. In thisvariation, although the flanges 238 intersect one another, they areindependently moveable.

FIG. 3C shows a variation of a device 200 where the capturing portion226 includes flanges 238 that are interwoven or connected with adjacentflanges 238. (Variations include bonding or otherwise joining theadjacent flanges together.) This feature provides the flanges 238 with ahigher radial strength that reduces the likelihood that the flanges 238bend or distort when moving in the body lumen or removing theobstruction.

FIGS. 3D to 3E illustrate additional variations of devices havingcapturing portions 226 that have a basket type configuration. As shown,the capturing portions 226 and surface 232 comprise a denser mesh oftraversing wires that ultimately lead to the traversing section 234 thatterminates in flanges 238 at the open proximal end 228. In suchvariations, a first portion of the traversing surface 232 that isadjacent to the open proximal end has a low coverage density relative tothe remaining portion of the capturing surface having a higher coveragedensity that eventually forms the permeable distal end 230. Thisconstruction lowers the lowering frictional resistance of the firstportion of the capturing surface when moving over or against theobstruction but allows the remaining portion of the capturing surface toencapsulate and secure the obstruction.

As shown in FIG. 3E, the wires diverge from the main bundle towards thedistal end of the capturing portion 226 to form the permeable distal end230. The permeable distal end 230 can actually have the sameconfiguration as the capturing surface 232. In other words, thepermeable distal end can simply be an extension of the capturing surfacethat extends over the distal end of the capturing portion.

Naturally, the divergence of the wires can occur over a length of thecapturing portion 226 rather than immediately at the distal end. Forexample, as show in FIG. 3D, the wires diverge towards a mid-section ofthe capturing portion and ultimately form the permeable distal end 230.

FIG. 3F illustrates a variation of a device 200 having multiplereinforcement rings 240. As noted above, the reinforcement rings provideadditional radial strength to the capturing portion 226 as the device200 moves within the body lumen and prevents distortion of the capturingportion 226. However, as noted above, the device will be fabricated toprovide varying regions of axial strength to allow for either the springeffect or the staged inversion discussed above. In any case, the rings240 do not need to extend around an entire circumference of a device,variations include any number of supports that extend between adjacenttraversing wires.

FIG. 3G illustrates another variation of a device 200 having a leadingwire 202 extending to a distal end 230 of a capturing portion 226. Inthis variation the capturing portion 226 is fabricated from a stent-typestructure. As noted above, it is within the scope of this disclosure touse any type of similar structure such as a laser cut tube, a chemicallyetched or photo etched tube, a polymer or metal injection moldedstructure, a basket, a filter, a bag, a coil, a helical wire structure,a mesh, a single wound wire, a film, a membrane, a polymer covering, ora plurality of crossing wires as the capturing portion 226 so long asthe device can be compressed to a small size for delivery and expandafter traversing the obstruction. The illustrated variation also shows acovering 270 located on the distal end 230 of the capturing portion 226.The length of the polymeric covering 270 can vary across the capturingportion 226 to prevent the obstruction from escaping as the device istranslated over the obstruction. Furthermore, the covering 270 can bepolymeric or a wire mesh. However, typically the covering has sufficientporosity to allow blood to flow through the device 200. In thisvariation, the flanges 238 form the translating surface.

FIG. 3H illustrates another feature for use with system describedherein. In this variation, the system includes a proximal capturingportion 260 located on an exterior of a delivery sheath 106. The mainbundle 202 extends through the sheath 106 to a distal capturing portion(not shown). As discussed below, the proximal capturing portion 260 canbe similar to the distal capturing portions 226 described herein withthe exception that the distal end 262 of the proximal capturing portionis open while the proximal end 264 of the proximal capturing portion isclosed. Furthermore, the proximal capturing portion 260 articulates withrespect to the sheath 106 much in the same manner as the distalcapturing portion 226 articulates relative to the main bundle 202. Inthis variation, the proximal end 264 of the proximal capturing portion260 is tapered or has a smaller profile than the remaining proximalcapturing portion 260. Such a feature may be useful to improve thedeliverability of the device to the intended site as well as to maneuveraround any obstructions within the body passage. In addition, as notedbelow, the proximal capturing portion 260 can be compressed about theobstruction to improve the ability of the system to remove theobstruction. The construction of the proximal capturing portion 260 canoptionally include variations having regions of differing axialstrength, or sections capable of generating spring force. Typically,since the proximal capturing portion 260 is not advanced distal to theobstruction, the need for staged inversion is not necessary.Accordingly, any number of capturing designs can be incorporated for theproximal capturing portion.

In some variations, the leading wire can extend to the proximal end ofthe system for manipulation by the physician. However, it is often thecase that the characteristics of the device must vary along its length.For example, when the device is intended for use in remote tortuousanatomy, the proximal section of the device is desirably stiffer (toadvance the distal portion of the device to the target anatomy).However, the distal section of the device must have properties that makeit suitable for the tortuous anatomy. In the case where devices are usedin the cerebral vasculature, the distal section must be extremelyflexible, while the proximal section should be stiff. In many cases,different material properties are required. A problem then arises inattempting to join different materials especially in the joining region.

Conventional joining methods include soldering, welding, gluing, thermaljunctions, etc. These joining methods produce an area having an increasein the stiffness of the device. For example, if two wires are to belaser welded together, then the section where they are joined has anoverlap which yields greater stiffness than the rest of the wire. Thisincreased area of stiffness is often balanced against the strength ofthe joined segment. If the joined region is too long, the strength willbe sufficient but the increase in stiffness often prevents navigationthrough the tortuous anatomy. IF the joined region is too short, thenthe device can navigate through the anatomy but the bond is weaker and arisk of failure increases.

FIG. 4A illustrates another variation of an improvement for use with thedevices described herein especially for use in tortuous anatomy such asthe cerebral vasculature. In this example, the capturing portion 226 isshow with a number of leading wires 204 extending proximally. To providethe desired characteristics, the leading wires 204 are joined in region196 to wires 198 having a structure that is suitable for the proximalanatomy (e.g., the wires are larger in diameter or stiffer). To enableuse of the device 200 in the cerebral anatomy without compromising bondstrength characteristics or flexibility of the device 200, the leadingwires extend a pre-determined region so that the bond region 196 isplaced out of the tortuous anatomy. Since the cerebral vasculature isapproximately 30 centimeters in length, the leading wires 204 can extendfor a length 195 of at least a predetermined length so that it remainsvery flexible when navigating the cerebral vasculature or other tortuousanatomy. In one example the length was 20 centimeters (but can be 30 ormore centimeters). By deliberately extending the leading wires 204 bylength 194, the length of the bond region 196 can be chosen toaccommodate the proximal anatomy (where a greater stiffness of the bondregion 196 can be accommodated). The length of the bond region 196 canvary depending on the application (e.g., from 2 to 20 cm for a deviceintended for cerebral the cerebral vasculature). However, the bond canextend along the entire proximal section of leading wire.

FIG. 4B illustrates an addition aspect of for use with devices describedherein where the main bundle 202 has a curved or bend portion 252. Thispre-set shape assists in orienting the capturing portion 226 within thebody passage since the bend will cause the device to bias against a wallof the body passage.

FIGS. 4C and 4D show cross sectional views taken along the line A-A inFIG. 4B. As shown, the wire form construction described herein allowsfor a number of configurations depending on the particular application.For example, the individual wires 204 (as discussed herein) maythemselves comprise a bundle of smaller wires or filaments. In addition,the wires can be selected from materials such as stainless steel,titanium, platinum, gold, iridium, tantalum, Nitinol, alloys, and/orpolymeric strands. In addition, the wires used in a device may comprisea heterogeneous structure by using combinations of wires of differentmaterials to produce a device having the particular desired properties.For example, one or more wires in the device may comprise a shape memoryor superelastic alloy to impart predetermined shapes or resiliency tothe device. In some variations, the mechanical properties of selectwires can be altered. In such a case, the select wires can be treated toalter properties including: brittleness, ductility, elasticity,hardness, malleability, plasticity, strength, and toughness.

The device may include a number of radiopaque wires, such as gold andplatinum for improved visibility under fluoroscopic imaging. In otherwords, any combination of materials may be incorporated into the device.In addition to the materials, the size of the wires may vary as needed.For example, the diameters of the wires may be the same or may vary asneeded.

In addition, the individual wires may have cross-sectional shapesranging from circular, oval, d-shaped, rectangular shape, etc. FIG. 4Cillustrates one possible variation in which a number of circular wires204 are included with a d-shaped wire 205. Moreover, the device is notlimited to having wires having the same cross-sectional shape or size.Instead, the device can have wires having different cross-sectionalshapes. For example, as shown in FIG. 4D, one or more wires 205 can havea different cross-sectional shape or size than a reminder of the wires204. Clearly, any number of variations is within the scope of thisdisclosure.

To illustrate one such example, a device can have 8-12 wires made of0.003″ round superelastic material (e.g., nitinol). The device mayadditionally have 2-4 wires made from 0.002″ platinum for fluoroscopy.Of the 8-12 nitinol wires, 1-4 of these wires can be made of a largerdiameter or different cross-section to increase the overall strength ofthe device. Finally, a couple of polymer fibers can be added where thefibers have a desired surface property for clot adherence, etc. Such acombination of wires provides a composite device with properties notconventionally possible in view of other formation means (such as lasercutting or etching the shape from a tube or joining materials withwelds, etc.). Clearly, any number of permutations is possible given theprinciples of the invention.

In another example, the device may be fabricated from wires formed froma polymeric material or composite blend of polymeric materials. Thepolymeric composite can be selected such that it is very floppy until itis exposed to either the body fluids and or some other deliveredactivator that causes the polymer to further polymerize or stiffen forstrength. Various coatings could protect the polymer from furtherpolymerizing before the device is properly placed. The coatings couldprovide a specific duration for placement (e.g., 5 minutes) after whichthe covering degrades or is activated with an agent (that doesn't affectthe surrounding tissues) allowing the device to increase in stiffness sothat it doesn't stretch as the thrombus is pulled out. For example,shape memory polymers would allow the device to increase in stiffness.

In another variation, one or more of the wires used in the device maycomprise a Drawn Filled Tube (DFT) such as those provided by Fort WayneMetals, Fort Wayne, Ind. As shown in FIG. 4E, such a DFT wire 252comprises a first material or shell 208 over a second material 210having properties different from the outer shell. While a variety ofmaterials can be used, one variation under the present devices includesa DFT wire having a superelastic (e.g., Nitinol) outer tube with aradiopaque material within the super-elastic outer shell. For example,the radiopaque material can include any commercially used radiopaquematerial, including but not limited to platinum, iridium, gold,tantalum, or similar alloy. One benefit of making a capturing portionfrom the DFT wire noted above, is that rather than having one or moremarkers over the capturing portion, the entire capturing portion can befabricated from a super-elastic material while, at the same time, thesuper-elastic capturing portion is made radiopaque given the core ofradiopaque material within the super-elastic shell. Clearly, anycomposite DFT wire 252 can be incorporated into the system and capturingportions described herein.

FIG. 5A shows a working end of a variation of a system 10 for removingan obstruction from a body lumen. In this variation, the system 10includes a main bundle 202 and capturing portion 226 extending out of amicro-catheter or catheter 102. The micro-catheter 102 can optionallyinclude a proximal foot 256 that can slide axially over main bundle 202and can be variably positioned in relation to the capturing portion 226.The proximal foot 256 can include any number of configurations apartfrom the petal/flange 258 configuration (i.e., the foot can be aballoon, coil, shoulder, etc. where such structures simply replace thepetals in FIG. 5A). In any case, the proximal foot 256 provides anincreased surface area that provides an opposing force to the capturingportion 226, where the opposing force aids the movement of theobstruction within the capturing portion 226. Alternatively, theproximal foot stabilizes the obstruction and keeps the obstruction frommoving with the capturing portion until the capturing portion envelopsthe obstruction.

The size of the proximal foot 256 can be adjusted depending on thetarget site anatomy. For example, a larger surface area can be employedif the target site is within a bifurcation of the body passage. The sizeof the proximal foot 256 can also be adjustable during the procedure.For example, in the case of a petal/flange 258 configuration, the petals258 can assume a larger size to initially stabilize the obstruction andthen reduce in size to allow the obstruction to be completely engulfedby capturing section 226.

The proximal foot 256 can extend from an interior of the catheter 102,such as from within the internal lumen of the catheter, or from anadditional lumen within a wall of the catheter. Alternatively, theproximal foot 256 can be permanently affixed to the catheter 102. Insuch a case, a separate catheter (without a proximal foot) can beemployed to traverse the obstruction for deployment of the devicedistally to the obstruction. Once the device is deployed, the catheterscan be exchanged to provide the proximal foot. In an additionalvariation, the proximal foot 256 can be affixed to a delivery sheath (asdescribed below) and be collapsed within the catheter, where advancementout of the catheter expands the proximal foot 256 so that it mayfunction as described above.

In an additional variation, a proximal capturing portion (as shown inFIG. 31H) can be used with a foot 256 that is located about the mainbundle 202. Such a variation may or may not include a distal capturingportion. Accordingly, the construction of the proximal capturing portion(as described herein to include sections of varying axial strength) canbe used to perform a push and relax technique (similar to that of thepull and relax technique described herein).

FIG. 5B illustrates another variation of the system 10 where the systemincludes a proximal capturing portion 260 located on an exterior of adelivery sheath 106. Naturally, the proximal capturing portion 260 couldalso be affixed to an exterior of a micro-catheter. The proximalcapturing portion 260 is similar to the capturing portions 226 describedherein with the exception that the distal end 262 of the proximalcapturing portion is open while the proximal end 264 of the proximalcapturing portion is closed. The proximal capturing portion can alsooptionally be configured to have regions of varying axial strength,spring rate, and various other features associated with the distalcapturing portion 226. In the illustrated variation, the capturingportion 226 and main bundle 202 move relative to the proximal capturingportion 260 to capture an obstruction. Furthermore, the proximalcapturing portion 260 articulates with respect to the sheath 106 much inthe same manner as the distal capturing portion 226 articulates relativeto the main bundle 202. As shown, the petals 238 on the open ends 228and 262 can interact to nest once the capturing portions 226 and 260 aremoved sufficiently close to one another. The outward force caused by theretained obstruction provides a frictional interaction between adjacentpetals/flanges 238 to maintain the nesting.

Variations of the device include additional structures, such as springs,hooks, barbs, etc, to cause the open ends 228 and 262 to interlock. Asnoted above, a separate catheter can be used to initially deploy thecapturing portion 226 beyond the obstruction. Although the capturingportions shown have the same configuration, the capturing portions 226and 260 used in any given system do not have to match in size, shape,and configuration. For example, the proximal capturing portion can beimpermeable to flow while the distal capturing portion allows flow. Inanother example, one basket may be undersized relative to the other toimprove nesting.

In any case, the construction of the system 10 shown in FIG. 5B includesopen ends 228 and 262 of capturing portions 226 and 260 that areunconnected. Accordingly, as the capturing portions 226 and 260 movetowards one another as a result of the main bundle 202 translatingrelative to the delivery sheath 106 the open ends are free to articulatearound the main bundle 202 and delivery sheath 106 respectively toremain expanded against the lumen wall.

FIGS. 5C to 5E illustrate a variation of a system for delivery of thecapturing portions 226 and 260. FIG. 5C shows the proximal 260 capturingportion affixed to a delivery sheath 106. In alternate variations, theproximal capturing portion 260 can be replaced with a proximal foot (notshown). As noted above, the main bundle or leading wires 202 extendsthrough the delivery sheath 106 and connects to the distal capturingportion 226 beyond the opening 228 of the distal capturing portion 200.The main bundle or leading wire 202 extends through the proximalcapturing portion 260. This allows the free ends of the capturingportions 228 and 262 to remain relatively unattached so that they canarticulate and conform to the curvature of the vessels (as discussedbelow). The capturing portions 226 and 260, main bundle 202 and deliverysheath 106 extend through a microcatheter 102.

FIG. 5D illustrates a state of deployment after the microcatheter 102traverses the obstruction (not shown). Once the microcatheter 102 isdistal to the obstruction, the distal capturing portion 226 deploys fromthe end of the microcatheter 102. As noted herein, the capturingportions can self-expand or can expand upon actuation by the physician.In any case, the distal capturing portion 226 should be sufficientlycollapsible to remain within the microcatheter 102 for deployment distalto an obstruction. To deploy the distal capturing portion 200 from thecatheter 102, the main bundle 202 can translate to push the distalcapturing portion 226 to eject it from the catheter 102. Alternatively,the microcatheter 102 can be withdrawn from the distal capturing portion226.

FIG. 5E illustrates the deployment state after the catheter 102 iswithdrawn proximal to the obstruction (not shown) and after the proximalcapture portion 260 is delivered from the microcatheter 102. As notedabove, the proximal capture portion 260 can be affixed to an exterior ofthe catheter, in which case the catheter may be either de-sheathed orexchanged. Alternatively, and as shown, the proximal capturing portion260 is affixed to a delivery sheath 106 and is fabricated to collapsewithin the microcatheter for ultimate deployment, whereby translatingthe sheath 106 delivers the proximal portion 260 from the microcatheter.

FIG. 5F shows another aspect of the system 10 where the proximal end 264of the proximal capturing portion 260 is collapsed or compressed aboutan obstruction 2 prior to translation of the obstruction 2 within thevessel. In this illustration, the proximal capturing portion 260 iscompressible by advancing the catheter 102 over the closed proximal end264 of the capturing portion 260. In such a case, the proximal capturingportion 260 is slidable within and relative to the catheter 102.Naturally, variations may include compressing the proximal end 264during translation of the obstruction 2. In either case, the proximalcapturing portion 260 can be compressed in a number of different ways.For instance, the proximal basket can be compressed using a catheter 102(as shown), or the delivery sheath 106, or any other number ofmechanisms (not illustrated).

As shown, the proximal end 264 can be compressed using a sheath 106and/or catheter 102 However, other means of compressing may be employed(e.g., a loop structure, a tube over the sheath, a draw-stringconfiguration, etc.) In use, once the distal capturing portion 226 isdeployed distally to the obstruction 2 and the catheter 102 is withdrawnproximal to the obstruction 2, the proximal capturing portion 260 isdeployed. As the proximal capturing portion 260 partially (or totally)engulfs the obstruction 2, the physician can collapse or compress theproximal capturing portion 260 to better secure the obstruction withinthe system 10.

It is noted that any number of shapes, configurations, as well as anynumber of joined wires may be contemplated to form devices under thepresent disclosure. However, variations of the invention includeselecting a number of wires to produce specific structural properties tothe device. For example, the devices can have any number of wires wherethe limit is determined by the ability to produce a device of asufficiently small size to access the area containing the obstruction.However, in some cases, it may be desired that wires are chosen toimpart specified characteristics. For example, in the illustratedvariation, the main bundle may comprise any number of wires that do notdiverge to form subsequent shapes in the device. In other words, not allof the wires forming a section are required to diverge to form anadjacent section. Instead, these non-diverging wires may simply “loop”back away from the device. In an additional variation, one or more wiresmay diverge to form a particular portion of the capturing portion (e.g.,the closed end, traversing wires, etc.). Then the wires can loop back toconverge again with the main bundle.

FIGS. 6A to 6E show one example of the deployment of a variation of adevice according to the present invention about an obstruction in avessel. The figures are intended to demonstrate the initial placement ofthe device immediately prior to removal of the obstruction.

FIG. 6A illustrates an obstruction 2 lodged within a body lumen orvessel 6. In the case where the vessel is a cerebral artery, theobstruction may result in an ischemic stroke. Using standardinterventional catheterization techniques, a microcatheter 102 andguidewire 104 traverse the obstruction. The microcatheter 102 may beadvanced through the obstruction 2. Alternatively, the microcatheter 102may “push” aside the obstruction and is advanced around the obstruction.In any case, the microcatheter 102 travels from the near end 3 (orproximal side) of the obstruction 2 to the far end 4 (or distal side) ofthe obstruction 2. It is noted that the catheter 102 may be centered oroff-center with respect to the obstruction 2. Furthermore, the devicemay or may not be used with a guidewire to navigate to the site andtraverse the obstruction.

Some variations of the device may be placed without an accompanyingguidewire. Moreover, the structures discussed herein may be directlyincorporated into a guidewire assembly where deployment may require asheath or other covering to release the components from constraint.

FIG. 6B illustrates deployment of a capturing portion 226 and mainbundle 202 of the device 200 from within the microcatheter 102 distal tothe obstruction 2. Accordingly, in most variations, the capturingportion 226 is designed to fit within the catheter 102 for delivery andexpand upon deployment. Alternatively, the device may be actuated toassume the desired shape (e.g., upon reaching a transition temperaturewhere one or more wires comprise a shape memory alloy). As shown, thecapturing portion 226 includes a traversing section 234 and a capturingsection 232. In some procedures the traversing section 234 engulfs theobstruction 2 with little or no complication as the main bundle 202,catheter 102, or sheath 106 pulls the capturing portion 226 in aproximal direction.

However, as discussed above, there may be some procedures where thedistal capturing portion 226 is deployed distal to an obstruction 2 thatis deposited within the vessel or lumen such that a steady translationof the capturing portion 226 will not engulf the obstruction 2. FIGS. 7Ato 7G illustrate some examples of such a situation. As shown in FIG. 7A,a sheath 106 might be able to traverse the obstruction 2 to deploy thedistal capturing portion 226 in preparation for engulfing theobstruction 2. FIG. 7B illustrates a condition where the traversingsection 234 engages the obstruction 2 but is unable to easily or fullyengulf the obstruction 2. However, in those variations where thecapturing portion 226 includes regions having different axial strength(as discussed above), continued pulling of the main bundle 202 in aproximal direction 120 causes the capturing section 234 to compress.When the capturing section 234 is constructed to function as spring, thedeformation of the capturing section 232 stores energy from the proximalmovement of the main bundle 202. This storing of energy allows thephysician to relax the pulling force 120 on the main bundle 202. FIG. 7Cshows a compressed capturing section 234. The energy stored in thecapturing section 232 gradually drives the open proximal end 228 of thetranslating section 234 over or along the obstruction 2. The physiciancan apply this “pull and relax” technique repeatedly until theobstruction is sufficiently captured by the capturing portion 226. Insome variations, the capturing section 234 remains compressed as theobstruction 2 finally breaks loose and removed.

FIG. 7D represents the situation where a distal capturing portion distalto an object 2 that is significantly embedded within a vessel or bodylumen. In such cases, the force required to remove the obstruction 2 maydamage the vessel or lumen. Such obstructions include atheroscleroticplaque or other immobile objects. As shown, when the distal capturingportion 226 is pulled once the proximal force 120 reaches a thresholdvalue (as determined by the construction of the capturing portion 226)the capturing portion 226 undergoes a staged inversion as the permeableend 230 enters the traversing section 232. In this variation, thepermeable end 230 actually enters the obstruction 2. The construction ofthe capturing portion 226 prevents flattening or expanding in diameter,where such movements would prevent removal of the capturing portion.Again, if the force applied by the capturing portion 226 breaks theobstruction 2 free. The obstruction 2 can be removed even though a partof the capturing portion 226 is within the obstruction 2 as shown inFIG. 2D.

FIG. 7E shows advanced inversion of the capturing portion 226 as thecapturing section 234 is now proximal to the traversing section 232. Thetraversing section 232 may be deformed upon inversion but will tapertowards the capturing section 234 as the capturing section 234 passesthrough the obstruction 2 (typically via an opening that was previouslycreated by advancement of a sheath 106 through or around the obstruction2).

FIG. 7F shows the capturing portion 226 nearly passing through theobstruction 2 so that it may be removed from the body. As shown in FIG.7G, the capturing portion 226 is now fully inverted and is in a statewhere it can re-enter a catheter for removal from the patient.

The construction described herein that allows for staged inversion ofthe capturing portion 2 provides a significant safety feature. Aphysician must undertake additional surgical intervention to remove anyretrieval device that has become lodged distally to an immobileobstruction. The ability of staged inversion allows the physician toinvert and remove the capturing portion 226 if application of apredetermined or threshold force is exceeded by proximal displacement ofthe device. This feature reduces the need for additional surgicalintervention to remove a retrieval device that would otherwise becomelodged or separated as a result of excessive forces being applied.

FIGS. 8A to 8B illustrate an additional benefit of affixing a leadingwire or bundle of wires 202 beyond a proximal opening 228 of a capturingportion 226. FIG. 5A illustrates a basket type structure 90 where a wire202 is affixed to a proximal end 92. As shown, as the leading wire 202pulls the basket 90 through tortuous anatomy 6, the force componentpulling away from an axis of the device 90 causes the proximal open end92 to constrict or reduce in size. As shown, as the proximal end 92approaches the obstruction 2 the perimeter of the end is not placedagainst the walls of the body passage 6. As a result, the constrictedopening 92 places an increased axial force on the obstruction 2 as thebasket 90 translates over the obstruction 2 (because the proximal end 92pushes against the obstruction rather than sliding around it), makingencapsulation of the obstruction more difficult and possible leading tovascular damage.

FIG. 8B shows a device 200 according to the principles disclosed herein.The leading wire 202 is affixed to the distal end 230 of the capturingportion 226. As the main bundle 202 is pulled through the curvedvascular path, the capturing portion 226 pivots or articulates about thebundle 202 and remains aligned with the axis of the vessel. As a resultany misalignment between the leading wire 202 and an axis of thecapturing portion 226 does not affect the open proximal end 228. Asnoted above, some closing of the open proximal end may occur, though itwill not be sufficient to interfere with the obstruction as thecapturing portion moves over the obstruction. Such a configurationallows the perimeter of the open proximal end 228 to remain against thewall of the passage 6. As shown, because the open proximal end 228 isnot constricted, the open proximal end 228 is better suited to slidearound the obstruction for eventual removal.

FIG. 8C shows withdrawal of the microcatheter 102 to the proximal side 3of the obstruction 2 and deployment of a proximal capturing portion 260(in alternate variations, a proximal foot can be used or the capturingportion 226 alone can be used). Again, the catheter 102 can be exchangedfor a catheter 102 having a proximal capturing portion 260.Alternatively, and as shown in the accompanying figures, the proximalcapturing portion 260 can be affixed to a delivery sheath 106 that isfed through the microcatheter 102.

As also shown in the figure, the main bundle 202 and capturing portionsbecome misaligned due to the tortuousity of the anatomy. However,because the capturing portions 226 and 260 are able to pivot orarticulate relative to the main bundle 202 and catheter 102 or sheath106, the open ends are able to remain against the lumen wall. Inconventional devices where the open end is attached to either a wire orcatheter, when the wire or catheter bends in the anatomy, the forcesexerted on the open ends deform or distort the end to assume a reducedprofile. Accordingly, the physician may have difficulty in removing anobstruction if the profile of the open end becomes reduced in size.Closing of the open end can also result in vascular damage if thephysician applies too much force in translating the device.

FIG. 8D shows movement of the capturing portions 226 and 260 adjacent tothe obstruction 2. The proximal capturing portion 260 can remainstationary or may be advanced relative to the distal capturing portion226. Regardless, the physician is able to ensnare the obstruction 2within the cavities defined by the capturing portions 226 and 260. FIG.8E illustrates the system as the two capturing portions are drawntogether. For purposes of clarity, the obstruction is not shown. Uponsufficient advancement of the capturing portion 226 and proximalcapturing portion 260 relative to one-another, flanges 238 on therespective open ends can interlock. This feature provides added safetyin removing the device as the obstruction is encapsulated between thetwo nested portions.

FIG. 8F illustrates a device 200 after securing an obstruction between aproximal 260 and distal 226 capturing sections. As shown, the capturedobstruction 2 is held between capturing portions 226 and 260 where theflanges 238 nest within one-another to “lock” the capturing portionstogether. In some variations of the device, one of the capturingportions can be undersized relative to the other. This configurationallows for the undersized capturing portion to become further compressedas the devices are pulled together. The compression of the capturingsurface then serves to further compress the obstruction 2 capturedwithin the device.

The capturing portions described herein can include coverings orwrappings so long as the other features of the device are not impaired.Such coverings can be located on both capturing portions 226 and 260,only one or more capturing portions. The covering can include a strandor fiber wrapped or woven about the section, a polymer film, or a dippedpolymer coating such as silicone, urethane, etc. The coating on eithercapturing portion can be solid or porous. In the latter case, blood cancontinue to flow through the coating. In one variation, the proximalcapturing portion 260 could employ a solid covering while the distalcapturing portion 200 could include a porous covering. In such a case,blood or other fluid flow could be temporarily halted by the presence ofthe solid covering to assist in removal of the obstruction.

FIG. 9 illustrates a variation of the system where the main bundle 202includes a medial foot 274. The construction of the medial foot 274 canbe similar to that of the proximal foot discussed above (e.g., wireslooped into a petal configuration.) However, the medial foot includes asurface area or diameter larger than a diameter of the main bundle. Inany case, the increased surface area of the medial foot 274 provides anincreased resistance to the obstruction 2 as the distal capturingportion 200 and main bundle 202 are pulled in a proximal directiontowards an obstruction 2. The medial foot 274 engages the obstruction 2to partially displace or loosen the obstruction from the walls of thebody passage. The medial foot 274 can be slidably located on the mainbundle such that after a threshold force, the medial foot moves withinthe distal capturing portion 200. The main bundle 202 can include anynumber of medial feet 274.

Although the illustrated variation shown above comprise open-ended,circular, looped or partial loop shape cross sectional areas, variationsof the capturing portions can include any number of shapes. For example,such a shape can include a circle, an arcuate shape, a partial circularshape, a loop, an oval, a square, a rectangle, a polygon, an overlappingloop, a pair of semi-circles, etc.) The various shapes may be heat setto be either self-expanding (i.e., superelastic) or the use of shapememory alloys can allow for the device to assume the particular shapeupon reaching a desired transition temperature.

The exemplary shapes discussed above permit the shaped section to adjustin diameter in response to placement in varying diameters of bodylumens. It is noted that a device may have different shaped sections ondifferent ends of the device.

While many different shapes are contemplated to be within the scope ofthis disclosure, the shapes will depend upon the ultimate application ofthe device. As noted herein, the illustrated examples have particularapplicability in retrieving obstructions from the vasculature.Accordingly, for these applications the shaped sections should form ashape so that they can expand against a vessel wall without causingtrauma to the vessel. For example, upon release from the catheter, theshaped section can assume their resting shape and expand within thevessel. The resting shape can be constructed to have a size slightlygreater than that of the vessel. Sizing the device relative to thetarget vessel may assist in placing the parts of the device against avessel.

In an additional aspect, the shaped sections may be designed to have anunconstrained shape that is larger than the intended target vessel orsimply different than a cross sectional profile of the intended vessel(i.e., not circular or tubular, but e.g., linear or other differentshape). In such an example, as the shaped section is released from thedelivery catheter, the shape section attempts to return to theunconstrained shape. In those variations where the unconstrained shapeis different from the circular profile of the vessel, the leading wireassumes a shape that accommodates the vessel but is more rigid andstable since its unconstrained shape is entirely different from that ofthe vessel. In other words, the shaped section continually exerts anoutward force on the vessel.

In yet another aspect, the shaped sections shown herein may notnecessarily lie in the same plane. Instead, they can be axially spacedby an offset. One benefit of constructing the device to have non-planarshaped section is that the configuration might allow for delivery of thedevice through a smaller microcatheter because the shaped sections donot interfere with one another when collapsed to fit within themicrocatheter.

Another aspect applicable to all variations of the devices is toconfigure the devices (whether the traversing filament or thesurrounding portion) for better adherence to the obstruction. One suchmode includes the use of coatings that bond to certain clots (or othermaterials causing the obstruction.) For example, the wires may be coatedwith a hydrogel or adhesive that bonds to a thrombus. Accordingly, asthe device secures about a clot, the combination of the additive and themechanical structure of the device may improve the effectiveness of thedevice in removing the obstruction. Coatings may also be combined withthe capturing portions or catheter to improve the ability of the deviceto encapsulate and remove the obstruction (e.g., a hydrophilic coating).

Such improvements may also be mechanical or structural. Any portion ofthe capturing portion can have hooks, fibers, or barbs that grip intothe obstruction as the device surrounds the obstruction. The hooks,fibers, or barbs 154 can be incorporated into any portion of the device.However, it will be important that such features do not hinder theability of the practitioner to remove the device from the body.

In addition to additives, the device can be coupled to an RF or otherpower source (such as 14 or 16 in FIG. 1A), to allow current, ultrasoundor RF energy to transmit through the device and induce clotting or causeadditional coagulation of a clot or other the obstruction.

The methods described herein may also include treating the obstructionprior to attempting to remove the obstruction. Such a treatment caninclude applying a chemical or pharmaceutical agent with the goal ofmaking the occlusion shrink or to make it more rigid for easier removal.Such agents include, but are not limited to chemotherapy drugs, orsolutions, a mild formalin, or aldehyde solution.

As for other details of the present invention, materials andmanufacturing techniques may be employed as within the level of thosewith skill in the relevant art. The same may hold true with respect tomethod-based aspects of the invention in terms of additional acts thatare commonly or logically employed. In addition, though the inventionhas been described in reference to several examples, optionallyincorporating various features, the invention is not to be limited tothat which is described or indicated as contemplated with respect toeach variation of the invention.

FIG. 10 illustrates one variation of a retrieval device 200 including adistal capture portion 226 coupled to one or more leading wires in theform of a main bundle 202. The main bundle extends through a sheath 106that includes a proximal capture portion 260. The configuration of theretrieval device 200 can incorporate the proximal and distal captureportions discussed herein as well as various other configurationsdiscussed in the commonly assigned patent applications noted above. Inaddition, the relative sizes of the various components shown in FIG. 10and discussed below are for illustrative purposes only.

An end 264 of the proximal capture portion 260 is affixed to a distalend of the sheath 106. However, as noted above, other variations arewithin the scope of the disclosure. The main bundle 202 can optionallyterminate at a handle 242. As noted above, in certain variations, themain bundle is joined to a stiffer wire or stiffer bundle of wires. Thisallows the device 200 to have a very flexible distal section with arelatively stiffer proximal section. FIG. 4A above, discusses placementof a joint at a location spaced from the distal section of the device soas to increase a bond strength but not impair the distal section'sflexibility. In any case, the device 200 can have a proximal bundle 203that comprises either the exposed wires or a covering/tube over thewires. In certain variations, the bundle or wire 202, 203 can beencapsulated with a coating.

The proximal end of the sheath 106 includes a sheath handle 244. Asdiscussed herein, axial movement of the bundle 202 or proximal bundle203 (typically at the handle 242) results in movement 126, ortranslation of the bundle within the sheath 106. This action moves thedistal capture portion 226 (as shown by arrows 126). In certainvariations, the device 200 is loaded into a microcatheter (not shown butdiscussed above) that is delivered to the site of the obstruction andcrosses the obstruction.

In some variations, the sheath hub 244 includes one or more locking hubs246. Where actuation (either axial or rotational) of the locking hub 246locks the main bundle 202 relative to the sheath handle 244 and sheath106. It follows that such locking action also locks the distal captureportion 226 relative to the proximal capture portion 260. A variety ofmethods can be employed to increase a frictional interference betweenthe locking hub 246 and the proximal bundle 203. As a result, when aphysician determines a length of an obstruction, the physician can set aspacing between the capturing portions 226 260 by locking the proximalbundle 203 relative to the sheath hub 244. Accordingly, the proximalbundle 203 can include any type of incremental markings to allow thephysician to readily determine a spacing of the capturing portions. Asillustrated, the sheath hub 244 can include additional injection portsto deliver fluid or other substances through the sheath 106.

As noted above, the device 200 can be used with micro-catheter. In thosevariations it is important that the device 200 is loaded withoutdamaging the distal bundle 202, capture portions 226 260, and/or sheath106. As a result, the device 200 can include an optional funnel 286 thatreduces the proximal capture portion 260 (and/or the distal captureportion 226) for loading within the microcatheter and/or sheath 106.

Another variation of the device 200 includes an insertion tool 280slidably affixed to the sheath 280. Because variations of the device 200can be extremely flexible, the insertion tool 280 can be used to providecolumn strength to the sheath 106, bundle 202 or other components as thedevice 200 is pushed into the microcatheter. The insertion toolcomprises a rigid section 282 and a frictional coupler 284. The rigidsection 282 has a column strength that supports the device 200 toprevent buckling. The frictional coupler 284 can be a flexible materialthat allows an operator to squeeze or grip the coupler 284 to create atemporary frictional interface between the loading tool 280 and thedevice 200 (typically the sheath 106). Such an action allows axialadvancement of the device 200 as the loading tool 280 is advanced intothe microcatheter. Once the rigid section 282 is fully inserted into themicrocatheter, the operator releases the frictional coupler 284 and canwithdraw the loading tool 280 from the catheter without withdrawing thedevice 200. The insertion tool 280 can also include an optional loadingtube 286 slidably coupled to the rigid section 282. When used, thefunnel 286 can withdraw the proximal and distal capturing portion 226260 within the loading tube 286. The loading tube 286 then couples to amicrocatheter allowing the capturing portions to advance therein as therigid section 282 and frictional coupler 284 advance the device 200relative to the loading tube 286.

FIG. 11A illustrates a funnel catheter 300 useful for retrieving objectsfrom vessels or body lumens. Typically, when a physician captures anobstruction in various retrieval devices, the device and the obstructionare easily removed from the body by withdrawing the device andobstruction into a sheath, guide catheter or introducer (“guidecatheter”). However, in some circumstances, a physician has difficultywithdrawing the obstruction loaded device within a sheath, guidecatheter or introducer. Specifically, one or more components of theretrieval device might become caught on an edge of the guide catheter.The concern may still remain even when using a guide catheter having anincreased diameter (such as when the retrieval device catches on oneedge of the guide catheter tip). Moreover, large guide catheters aredifficult to advance within various parts of the anatomy. As a result,the obstruction loaded device must travel further. Movement of theobstruction loaded device within the body creates the risk that theobstruction will detach or break apart and cause additional adverseconsequences.

The funnel catheter 300 includes a first and second slotted funnels 330,340 located at the distal end of an inner shaft 302. Each funnel 330 340comprises a number of extensions or tines 332 342. The inner shaft 302can be cut to produce the first tines 332. Alternatively, the firsttines 332 can be affixed to a portion of the inner shaft 302. The secondslotted funnel 340 is offset in both a proximal and rotational positionrelative to the first slotted funnel 330. The purpose of this dualoffset is discussed in detail below. As shown, the second funnel 340 canbe a slotted tube that is affixed over the inner shaft 302. In analternate variation, a plurality of second tines 342 can be locatedabout the inner shaft 302 to form a second slotted funnel 340. As shownin FIG. 11B, the tines 332 342 can be configured to expand outward (ifnot restrained) via use of a coil or other spring-type means.Alternatively, they can be actuated to expand outward. However, in mostcases, the tines 332 342 can expand passively upon entry of theretrieval device 200. The expansion of one or both funnels assists inreceiving the retrieval device. In additional configurations, one ormore funnels can be designed so that they remain in a cylindrical shaperather than expand outwards (as shown in FIG. 11C). Variations of thefunnel catheter 300 can include configurations having one or morefunnels, or configurations where the tines spaced or adjacent (or acombination thereof).

FIG. 11C also illustrates the dual offset nature of the dual funnelcatheter 300. The first offset is a linear offset 316 such that thedistal ends of the first tines 332 or funnel 330 extends beyond a distalend of the second tines 342 or second funnel 340. The second offsetcomprises a rotational offset (denoted by rotational angle A). Forexample, the illustrated rotational offset A is 45 degrees. However, therotational offset can vary depending on the particular application. Inmost variations, the rotational offset A will place the second tines 342over the gaps or spaces between the first tines 332. The number of tinescan vary depending on the application. Variations of the funnel cathetercan include discontinuous funnels with two or more tines.

Turning back to FIG. 11A, the funnel catheter 300 can optionally includeany number of medical fittings or components. As shown, the catheter 300includes a hemostasis valve or hub 306 at the proximal end. Thehemostasis valve 306 can include a fluid side port 308 for delivery offluid through the catheter 300. The catheter 300 can also include one ormore radiopaque markers 310 so that the location of the funnel orfunnels 330 340 can be identified via non-invasive imaging (e.g., underfluoroscopy). The funnel catheter 300 can also optionally include one ormore markers 312. Such markers are useful to inform a physician (who isonly able to view the proximal end of the device 300) of the distance tothe first or second funnel. As a result, the physician will be able todetermine whether the funnels are advanced out of the guide catheter.FIG. 11A also shows the funnel catheter 300 as including a loading tool314. The loading tool 314 can be advanced over the funnels 330 340 tocompress the funnel when loading into a guide catheter or other sheath.

FIGS. 12A to 12C provide an illustrative example where use of a funnelcatheter 300 aids in removal of an obstruction 2 loaded within aretrieval device 200.

As shown in FIG. 12A, attempting to remove the obstruction 2 whenengulfed in the retrieval device 200 creates a risk that one or moreportions of the device 200 become caught on the guide sheath or accesscatheter 108. In some cases, the physician can simply engage the device200 against the distal end of the guide sheath 108 and withdraw untilthe obstruction 6 and device 200 are located in an acceptable area ofthe body or withdrawn entirely from the body. For example, in certainsituations, the obstruction 6 and device 200 can be withdrawn with theguide sheath 108 until all components reach a high flow, non-criticallocations (e.g., the groin area). In the case of a clot, a clotdissolving substance (TPA) can then be applied to dissolve and removethe clot. Alternatively, the physician can attempt to aspirate throughthe guide sheath 108 in an attempt to draw the entire retrieval device200 and obstruction 2 within the guide sheath 108. In yet anothervariation, the physician can advance fibers or guide wires out throughthe guide sheath 108, then withdraw the obstruction 2/retrieval device200 and attempt to use the fibers or guide wires as a moveable surfaceto capture the device 200. Furthermore, the physician can attempt to usea variety of existing devices (e.g., the FastCath provided by GenesisMedical Inc., the Merci Retriever provided by Concentric Medical Inc.,or any commercially available snare or distal protection device) toremove the engulfed obstruction 2 from the body.

In some variations, the capturing portions discussed above can beconstructed to improve their ability to be withdrawn into a guidesheath. For example, increasing the number of petals or flanges on thetraversing sections increases the probability that the distal flangesnest within the proximal capturing portion. Alternatively, or incombination, the petals 238 on the distal capturing portion can bestaggered in length or position to ease insertion into the proximalcapturing portion. In another variation, the petals 238 shape orcurvature can be adjusted so that they do not flare outward.

FIG. 12B shows a distal end of a funnel catheter 300 as it receives anobstruction 2 loaded retrieval device 200. As shown, the tines 332 ofthe first funnel 330 receive the device 200. The tines 332 minimize thelikelihood that the device 200 becomes caught. The limited surface areaof the tine 332 (combined with the rounded tines 332 342) produces atendency for the device 200 to deflect away from the tines as it iswithdrawn into the funnels. The second funnel 340 (being rotationallyoffset from the first funnel 330 provides coverage over the spacesbetween the first tines 332 thereby assisting in nesting of the device200 within the funnels. Ultimately, the device 200 and obstruction 2 arewithdrawn into a guide sheath 108 and removed from the body.

FIGS. 12C to 12D show additional variations of funnel catheter 300. FIG.12C shows a single funnel 330 having a plurality of tines 332. FIG. 12Dillustrates a dual funnel catheter 300 having a discontinuous firstfunnel 230 and a second funnel 346. The second funnel 346 can be acontinuous funnel so long as it is able to retract within the guidesheath 108. As shown, the second funnel 346 can include a single slit348 that allows the funnel to compress within the guide sheath 108. Inaddition, the variation of FIG. 12D can be used without the firstdiscontinuous funnel 330. Accordingly, as the retrieval device 200 andclot 2 approach the funnel 346 and enters the funnel, furtherwithdrawing the retrieval device 200 causes squeezing of the retrievaldevice 200 and obstruction 2. In yet another variation, the funnel 346can incorporate a drawstring to compress the funnel 346 once theretrieval device 200 and obstruction are located therein.

FIG. 13A to 13B illustrates another variation of a funnel catheter 350suited to remove a retrieval device 200 from the body. As shown in FIG.13A, the funnel catheter 350 includes a first shaft 352 and a secondshaft 354 slidably located therein. A mesh 370 is fused to each shaft352 354 at a distal location 362 364. Accordingly, relative movement ofthe shafts 352 354 (either the first shaft 352 can be pushed or thesecond shaft 354 can be pulled) creates a funnel shape 372 as the meshportion affixed to the second shaft 354 is inverted within the remainderof the mesh 370. It is noted that in some variations of the system, themesh funnel funnels are combined with the tine based funnels describedabove. Such that one funnel comprises the tines while the othercomprises the mesh structure described herein.

In another variation, a third distally located capture portion (similarto a distal capture portion) can be used to draw the retrieval devicewithin a guide sheath. In such a variation, the third capture portioncan be a larger distal capture portion and when the retrieval deviceengulfs an obstruction, the third basket portion can be proximallywithdrawn to capture the retrieval device and obstruction.

As illustrated in FIG. 13B, as the retrieval device 200 and obstruction2 approach the funnel catheter 350, the distal attachment points 362 364of the shafts 352 354 are moved together to invert the mesh 370 and forma funnel 372. The retrieval device 200 can then be withdrawn into thefunnel. This design allows for the retrieval device 200 to be fullywithdrawn into the catheter 350 while the funnel 372 is expanded.Alternatively, the funnel 372 can be used to compress the retrievaldevice 200 and obstruction 2 prior to withdrawal into the catheter 350.

The mesh 370 can include any medically acceptable material such as anitenol braid. Furthermore, the mesh allows for flow through the vesselor lumen while expanded. However, additional variations of the devicecan include a solid layer of material substituted for the mesh.

FIGS. 13C to 13E illustrate another variation of a funnel catheter 350suited to remove a retrieval device 200 from the body. As shown in FIG.13C, the funnel catheter 350 includes a first shaft 352 and a secondshaft 354 slidably located therein. A mesh 370 is joined only the rearshaft 354 at a distal location 362. The end of the mesh 370 is free atthe distal end of the device 350. The mesh 370 is sized at a distal end371 to neck down. Accordingly, as the distal shaft moves rearward, themesh 370 is unsupported. The necked section 371 of the mesh allows fordistal advancement of the device 200 through the neck portion 371.However, as shown by FIG. 13D, rearward movement of the device 200causes engagement with the neck portion 371. Further rearward movementof the device 200 causes the unsupported mesh 370 to form a funnel shape372 as shown in FIG. 3E. The funnel shape allows for the retrievaldevice 200 to be fully withdrawn into the catheter 350 while the funnel372 is expanded. Alternatively, the funnel 372 can be used to compressthe retrieval device 200 and obstruction 2 prior to withdrawal into thecatheter 350. To compress the funnel, the device 200 can be advanced outof the funnel and away from the mesh 370. Next, the distal shaft 352 canbe advanced through the neck portion 371 of the mesh 370 to receive thedevice 200. In another variation, the device 350 can include a singleshaft 354 where the mesh 370 can extend beyond the shaft 354. The meshcan be heat set to assume a funnel shape upon the application of acurrent or as it reaches body temperature. In another variation, themesh 370 can comprise a super-elastic material that assumes the shapeshown in FIG. 13E when released from a constraining member.

FIGS. 13F to 13G illustrate yet another variation a funnel catheter 350suited to remove a retrieval device 200 from the body. In thisvariation, the funnel catheter 350 includes a single shaft 354 having amesh 370 is fused to a distal location 364. The mesh 370 is free at aproximal side. The mesh is also pre-formed to assume a funnel shape asshown in FIG. 13G. Accordingly, upon delivery the mesh 370 can beconstrained (e.g., via a sheath, or other removable restraint). Once therestraint is removed, the mesh 370 expands to form a funnel 372.

FIGS. 14A to 14D illustrate additional concepts for use with variousretrieval devices 200. FIG. 14A illustrates a distal capturing portion226 and a proximal capturing portion 260 where the proximal capturingportion includes a covering 212 (e.g., a polymeric covering or a wire orfiber wound about the flanges 238). The covering 212 prevents theflanges 238 of the distal capturing portion 226 from flaring outside ofthe proximal capturing portion 260.

FIG. 14B illustrates a variation of a reentry sleeve where tines 332 ofthe reentry sleeve 302 include protrusions 214 on an inner surface. Theprotrusions 214 cause the tines 332 to splay out as the retrieval device200 is withdrawn within the tines 332. As the reentry sleeve 302 iswithdrawn in a guide catheter (as discussed above) the protrusions serveto compress the retrieval device 200 even further.

FIGS. 14C and 14D illustrate variations of a wire or fiber 218 affixedto the flanges 238 of a distal capturing portion 226 to assist incompressing the flanges 238 prior to entry within a guide sheath. Asshown in FIG. 14C the fiber 218 can be affixed to a suture ring 216. Asthe fiber 218 is pulled, the suture ring 216 compresses the flanges 238to prevent outward flaring. In FIG. 14D, one or more fibers 218 areaffixed to one or more flanges 238. Once the obstruction is captured,the fibers can be pulled to draw the flanges 238 closed.

Various changes may be made to the invention described and equivalents(whether recited herein or not included for the sake of some brevity)may be substituted without departing from the true spirit and scope ofthe invention. Also, any optional feature of the inventive variationsmay be set forth and claimed independently, or in combination with anyone or more of the features described herein. Accordingly, the inventioncontemplates combinations of various aspects of the embodiments orcombinations of the embodiments themselves, where possible. Reference toa singular item, includes the possibility that there are plural of thesame items present. More specifically, as used herein and in theappended claims, the singular forms “a,” “and,” “said,” and “the”include plural references unless the context clearly dictates otherwise.

It is important to note that where possible, aspects of the variousdescribed embodiments, or the embodiments themselves can be combined.Where such combinations are intended to be within the scope of thisdisclosure.

We claim:
 1. A medical device for removing an obstruction from a bodypassage, the medical device comprising: at least one leading wire havinga first end and a second end; a capturing portion having a surfaceextending between an open proximal end and a permeable distal end; wherethe capturing portion is formed from the at least one leading wire suchthat the group of wires extends through an interior of the basket anddiverges to form the permeable distal end, the group of wires extendback in a proximal direction to form the capturing portion; and wherethe surface of the capturing portion comprises a translating surface anda capturing surface, each being configured so that a translating surfaceaxial strength is greater than a capturing surface axial strength,wherein application of a tensile force on the at least one leading wirecauses axial compression of the capturing surface before causing axialcompression and deformation of the translating surface as the capturingportion engages the obstruction.
 2. The medical device of claim 1, wherethe capturing portion is formed such that articulation of the capturingportion relative to the min bundle does not cause the open proximal endto reduce in size.
 3. The medical device of claim 1, where the capturingsurface is configured to generate a spring force against the translatingsurface when a proximal force applied by the at least one leading wireof wires compresses the capturing surface against the translatingsurface when encountering resistance from the obstruction, where thecapturing surface is configured to have a sufficient axial stiffness todirect the spring force and proximal force to the open proximal end asthe open proximal end engages the obstruction where the capturingsurface is also sufficiently flexible to conform to a shape of thevessel.
 4. The medical device of claim 1, where the capturing portion isconfigured so that when the open proximal end of the translating surfaceengages resistance equal to or greater than a threshold force, proximalmovement of the at least one leading wire inverts the capturing surfacewithin the translating surface and reduces a size of the capturingportion.
 5. The medical device of claim 4, where the capturing surfaceand translating surface are configured to invert upon continued proximalmovement of the at least one leading wire such that the translatingsurface moves distally to the capturing surface.
 6. The medical deviceof claim 1, where the at least one leading wire is joined to a proximalbundle, where the proximal bundle comprises a stiffness greater than theat least one leading wire wires and where the at least one leading wireextends for a pre-determined distance from the permeable distal end toallow navigation of a distal portion of the medical device within thecerebral vasculature.
 7. The medical device of claim 6, where thepre-determined distance is at least 20 cm.
 8. The medical device ofclaim 1, where the capturing surface has an increased frictionalresistance as compared to the translating surface, such that thecapturing surface engages the obstruction for removal of theobstruction.
 9. The medical device of claim 1, where the open proximalend further comprises a plurality of flanges extending from thetranslating surface.
 10. The medical device of claim 9, where theflanges extend radially away from an axis of the capturing portion. 11.The medical device of claim 1, where the capturing portion isself-expandable.
 12. The medical device of claim 1, where at least aportion of the capturing surface comprises a structure selected from thegroup consisting of a basket, a filter, a bag, a coil, a helical wirestructure, a mesh, a single wound wire, and a plurality of crossingwires or a combination thereof.
 13. The medical device of claim 1, wherethe at least one leading wire includes at least a first wire and asecond wire where the first and second wire each have differentcharacteristics.
 14. The medical device of claim 13, where thecharacteristics are selected from a group consisting of material,cross-sectional shape, and cross-sectional size.
 15. The medical deviceof claim 1, where the at least one leading wire includes at least oneshape memory alloy wire.
 16. The medical device of claim 1, where the atleast one leading wire includes at least one wire selected from thegroup consisting of a superelastic wire, a polymeric wire, or a metalalloy.
 17. The medical device of claim 16, where the metal alloycomprises an alloy selected from the group consisting of stainlesssteel, titanium, platinum, gold, iridium, tantalum, nitinol, andcombinations thereof.
 18. The medical device of claim 1, furthercomprising at least one radiopaque material located on the capturingportion.
 19. The medical device of claim 1, where the group of wirescomprises a plurality of individual wires and where one of theindividual wires each comprise a bundle of smaller wires.
 20. Themedical device of claim 19, where the individual wire comprises asuper-elastic outer shell and an inner core of a radiopaque material.21. The medical device of claim 20, where the inner core comprises amaterial selected from a group consisting of platinum, iridium, gold,and tantalum.
 22. The medical device of claim 1, where the capturingportion is jointless. returns to the group of wires after forming a partof the capturing portion.
 23. The medical device of claim 1, where theat least one leading wire is surrounded by a coil or coiled wire.